code: def test_forward_mat_multi_batch(self):
      test_x = torch.randn(2, 3, 4, 3)
      mean = self.create_mean()
      self.assertEqual(mean(test_x).shape, torch.Size([2, 3, 4]))
  
file_path: gpytorch/gpytorch/test/base_mean_test_case.py
imports: from abc import abstractmethod
  import torch
  from .base_test_case import BaseTestCase
label_desc: Use image node_id 5 for calling the BaseMeanTestCase obj's underlying member method code with example usage: obj.test_forward_mat_multi_batch() without return types